Sewer pipe cleaning vehicles are used to remove debris from clogged and partially clogged pipes that typically range in size between 2 and 60 inches in internal diameter. These vehicles are typically transported adjacent to a pipe access, e.g., a manhole. A first hose is coupled to a high pressure pump, and a second pump is connected to a sludge container that is maintained at a vacuum. The first hose has a nozzle at its end opposite the high pressure pump. The two hoses are lowered into a desired pipe to be cleaned. Water is pumped from the high pressure pump through the first hose and sprayed out of the nozzle into the pipe to loosen debris from the pipe interior wall. Simultaneously, a vacuum is applied to suck debris-laden water through the second hose from the pipe into the vacuum container.
For many years pipe cleaning vehicles have been limited by how much supply water and debris-laden water could be held in the vehicle. This was because the supply water container would become depleted and would need to be refilled, or because the debris-laden water tank would become filled and would need to be emptied. Thus, the cleaning process would have to be stopped until at least one of these two functions were performed. This would normally entail many time consuming tasks including driving the vehicle off-site. This has made many prior art pipe cleaning vehicles impractical and simply too ineffective for use in cleaning many pipes because of their limited capacity to clean.
In an attempt to overcome these drawbacks, some prior art cleaning vehicles, such as the one disclosed in U.S. Pat. No. 4,377,475, have been made with water-recycling systems. These vehicles filter the debris-laden water sucked-up from the pipe and use the filtered water to spray back into the pipe. However, many of these prior art cleaning vehicles have been constructed with a waste of components, and they may not fully meet the necessary operational requirements and/or may not work economically. For example, they have been extremely susceptible to failure of the vacuum pump and to failure of the high pressure pump. Moreover, they have not sufficiently cleaned the water for certain recycling needs. Additionally, they still have been susceptible to being rapidly filled, forcing the vehicle to be transported off-site for drainage of the sludge tank.
Another drawback of prior pipe cleaning vehicles that recycle the water has been the pump and system used for creating a vacuum to draw water up from the pipes. Some of the vacuum pumps used have been positive displacement vacuum pumps. However, these pumps have significant drawbacks and have had a relatively high failure rate. Some prior pipe cleaning vehicles have used a liquid ring vacuum pump. However, these pumps have created a problem in these vehicles because the water used by these pumps to create the seal normally gets very hot, requiring the operator of the vehicle to stop the cleaning process and cool the pump down. Moreover, these pumps have required large and bulky external heat exchangers having many pipes in an attempt to cool this heated water.
Yet another drawback of prior pipe cleaning vehicles that recycle the water has been poor filtration of the water being recycled, causing the high pressure pump to fail prematurely. This has caused some high pressure pumps to fail after only 30 hours of use. Additionally, nozzles used for cleaning the pipes have failed prematurely due to the poor filtration of the water.
Thus, an improved pipe cleaning vehicle was needed.